Changes in pulmonary blood flow during gaseous and partial liquid ventilation in experimental acute lung injury

Background It has been proposed that partial liquid ventilation (PLV) cause s a compression of the pulmonary vasculature by the dense perfluorocarbons and a subsequent redistribution of pulmonary blood flow from dorsal to bett er-ventilated middle and ventral lung regions, thereby improving arterial o xygenation in situations of acute lung injury, Methods: After induction of acute lung injury by repeated lung lavage with saline, 20 pigs were randomly assigned to partial liquid ventilation with t wo sequential doses of 15 ml/kg perfluorocarbon (PLV group, n = 10) or to c ontinued gaseous ventilation (GV group, n = 10), Single-photon emission com puted tomography was used to study regional pulmonary blood flow. Gas excha nge, hemodynamics, and pulmonary blood now were determined in both groups b efore and after the induction of acute lung injury and at corresponding tim e points 1 and 2 h after each instillation of perfluorocarbon in the PLV gr oup. Results: During partial liquid ventilation, there were no changes in pulmon ary blood flow distribution when compared with values obtained after induct ion of acute lung injury in the PLV group or to the animals submitted to ga seous ventilation. Arterial oxygenation improved significantly in the PLV g roup after instillation of the second dose of perfluorocarbon. Conclusions: In the surfactant washout animal model of acute lung injury, r edistribution of pulmonary blood flow does not seem to be a major factor fo r the observed increase of arterial oxygen tension during partial liquid ve ntilation.